The conceptual issue addressed in this work may be stated in the form of a question: When an organism experiences a chain of stimuli in the form S1`S2`S3`S4`S5, how does that organism come to appreciate that sequence? Must the learning of that chain be accomplished, at least for experimentally inexperienced subjects, via some form of extensive reinforced training, as is typically done? Or, is it possible that with sequential information so central to life, that the sequential nature of the chain is learned essentially via exposure to that information? The work seeks to develop approaches to the learning of sequential information that meet the following criteria: 1. The entire set of serially-ordered stimuli are present from the outset of training; 2. Reinforcement is not made explicitly contingent upon correct responding; 3. As a function of 1 and 2, the acquisition of a sequence can be assessed after a relatively short amount of training. To accomplish these objectives, the proposed work will adapt methods used in the study of implicit learning with human subjects for use with highly-endangered New World primate species, Cotton-top tamarins (Saguinus oedipus). Implicit learning may be broadly defined as learning that occurs in the absence of explicit instructions to learn. The important role that implicit learning has come to play in the study of human cognition makes it valuable to understand its comparative origins. It might be argued that there can be no adequate nonhuman analog of human implicit learning, inasmuch as the there can be no assessment of subjects'awareness of a pattern, one of the features of human implicit learning that has conferred so much interest in it. As counterpoint, it is argued herein that an implicit learning procedure for a nonhuman would present patterned information to subjects, but reinforcement would not depend on learning the pattern. The question under discussion would then be whether in this format a nonhuman learns more than is demanded by the experimental contingencies. The impact of the proposed work on the students who gain participation in science through this project forms a vital component of this application. At Holy Cross the research and educational missions of the institution are inseparable. The Principal Investigator and other faculty members teach via their laboratories. One of the hallmarks of the Principal Investigator's animal cognition laboratory is students'participation in original research, their presentations at regional and national meetings, and their co-authorship on scholarly publications. AREA will enhance those activities and will further the intimate relationship between research and teaching by supporting undergraduate research assistants during the academic year and summers for the next three years. Importantly, the proposed work will be conducted at the New England Primate Research Center (NEPRC), one of eight federally-funded primate research centers in the country. The prospect of studying tamarins at NEPRC represents a rare opportunity, one not often afforded faculty members and students at undergraduate liberal arts institutions. PUBLIC HEALTH RELEVANCE: Developing animal models of implicit learning holds the promise of providing techniques for investigating the boundary conditions under which implicit learning occurs. Importantly, there are a number of indications that implicit learning may be intimately involved in a number of cognitively-related disorders, ranging from schizophrenia to dyslexia. In humans, some forms of implicit learning are conserved in aged subjects, whereas many of the usual forms of learning are diminished.